Timer.



PATENTED SEPT. 1, 1908.

C. N. ISAAGS.

TIMER.

APPLIGATION FILED DEG.13, 1907.

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CLARENCE NoEL teams, or NEWARK, NEW JERSEY.

TIMZER.

Specification of Letters Patent.

Patented Sept. 1, 1908.

Application filed December 13, 1907. Serial No. 406,276.

To all whom it may concern:

Be it known that I, CLARENCE; NoEL IsAACs, a subject of the King of Great Britain, and aresident of Newark, in the county of Essex and State of New Jersey, have invented a new and Im roved Timer, of which the following. is a fu clear, scription,

This invention relates to certain improvements in timers adapted-for use in connection with internal combustion engines, for closing the circuit through the igniter to produce the explosion, and the object of the invention is to so construct the timer that the circuit will be closed a substantially uniform length of time for each explosion, irrespective of the speed at which the engine may be running.

T he movable terminal which is intermittently brought into engagement with the other terminal to close the circuit, preferably and exact deis provided with lost motion connections and engages with a stop just prior to its engage ment with the stationary terminal. The movable terminal or contact arm is thus momentarilystopped, and when it does pass the obstruction, it contacts with and passes the terminal closely adjacent thereto under the influence of a spring, thetension of which is not in any way-dependent upon the speed at which the shaft bearing the contact arm is rotated. Reference is to be had to the accompanymg drawings, forming a part of this specification, in which similar characters of reference indicate corresponding parts in all the figures, and in which Figure 1 is a central longitudinal section I 6 through a timer constructed in accordance with my invention, said section beingtaken on the line 11 of Fig. 2; Fig. 2 is an end view of the operating parts of the timer, the inclosing casing being cut on the line 22 of Fig. 1 and Fig. 3 is an end view of one of the stationary terminals or brushes.

The essential features of my timer include a pivoted contact arm, the terminal portion of which is secured to the rotating'shaft by lost motion connections, a stationary terminal, and an obstruction adjacent thereto, serving to retard the contact arm.

In the specific embodiment of my inven tion which I illustrate in the accompanying drawings, I employ a rotating shaft 10, adapted to be continuously rotated from the crank shaft of the engine, and mounted on the shaftadjacent the end thereof is asuitable casing, 11, having peripheral walls 12 and a removable end plate or cover 13. The shaft continuously rotates while the casing remains substantially stationary, although rotatable through a portion of a revolution to advance or retard the time of circuit-closing contact between the terminals, as is common in the art. The circumferential wall 12 of the casing carries a plurality of brushes or stationary terminals, and an obstruction adjacent each of these terminals, while the shaft bears a contact arm rotatable to engage with the several terminals in succession. The stationary terminals are insulated from the casing wall, that is, if the latter is madeof conducting material as in the present 1nstance, and it is connected to a wire at its outer end, leading to the igniter or spark coil, according to the nature of the ignition system. Each terminal preferably includes a radially-disposed bolt 14, extending through the casing wall and insulated therefrom by a jacket 15 and supporting at its inner end two oppositely disposed brushes 16, between which the end of the contact arm passes, the brushes being spaced apart by a portion 15 of the bolts 14. The inner endof the bolt is preferably rectangular in cross section, and the two brushes are preferably L-shaped. The two brushes are rigidly secured to 0 p0- site sides of the rectangular end of the olt, and are provided with portions 1Zextend ng substantially circumferentially of the casing or along the path taken by the end of the contact arm. of its terminal portion 17, is bent inwardly to reduce the distance between the two, and then bent outwardly again, as clearly illustrated in Fig. 3. The outer end of each bolt constitutes a binding post, to which the wires 18 are connected. Adjacent each terminal or air of brushes, is an obstruction 19, prefera ly supported by the bottom wall of the casing and extending to a point adjacent the several terminals.

The rotatable shaft 10 carries an arm formed of two sections, one section 20 keyed or otherwise rigidly secured to the shaft and the other section 21 pivoted adjacent the outer end of the section 20,. The section 20 carries a laterally extending shoulder or projection 22, and the section 21 carries a shoulder or projection 23, normally extending substantially parallel to the projection 22. The

Each brush along the length terminal portions of these projections are connected by a coil spring 24, normally tending to draw them toward each other and to hold the arm sections and 21 in substantially the same straight line. The section 20 preferably carries a stop 25 with which the section21. engages to limit the movement caused by said spring. The end of the arm section 2-1 is adapted to engage with the several obstructions 19, and is somewhat thinner than the heads of the several bolts 14, whereby it may pass between the brushes without contacting therewith, save at their inwardly bent portions.

In the operation of my improved device, one wire from the battery or other source of electrical energy, is connected to the engine frame. whereby the current may pass through the shaft 10 to the end of thecontact arm, while the igniters of the several engine cylinders are connected to the wires 18. As the shaft 10 rotates, the contact arm section 21 engages with theobstruction 1!) and is retarded, while the other arm section 20 continues uninterrupted. The spring 24 is expanded until the. end of the arm section. 21 is bent backward so that it can pass the end of the obstruction 18). The instant it reaches the position 21 shown in dotted lines in Fig. 2, the spring instantly pulls the arm section 21 through between the brushes, so that it makes and breaks circuit therewith for a very brief interval. The forward motion of the arm section is due almost entirely to the spring, so that the speed of rotation of the shaft 10 has very little, if any, bearing upon the length of time the contact arm is in engagement with the stationary terminals. Thus, the same amount of current is used and the spark passes for the same length of time, whether the engine be running at low speed or at high speed, and, furthermore, it is impossible for the terminals to be in contact with each other as the engine stops.

In the constructions commonly employed, if the circuit be closed a sufficient time to produce the desired spark and secure the ignition at high speed, then the batteries are wasted and the current passed for an unnecessary length of time at low speed. Fur thermorc, in the ordinary construction, should the engine stop in one portion of the revolution, the circuit will be closed continuously and the batteries exhausted, while the engine is standing still. These dilliculties are entirely overcome by means of my invention.

Having thus described my invention, I claim as new and desire to secure by Letters Patent:

1. In a circuit closer, a terminal, a pivoted arm adapted to intermittently engage therewith to close an electric circuit, and an obstruction adjacent said terminal and adapted to engage with said arm prior to the engagement of the latter with said terminal.

2. In a circuit closer, a rotatable shaft, an arm secured thereto and including lost motion connections, a spring for holding said arm in one of its limiting positions, a termlnal adapted to be engaged by said arm to close an electric'circuit, and an obstruction in the path of said arm adjacent said terminal.

3. Ina circuit closer, a terminal, a r0tatable shaft, an arm carried by said shaft and including two sections pivoted together, a spring for holding said sections in a predetermined position in respect to each other, and an obstruction adjacent said terminal and in the path of said arm, whereby the end of said arm is retarded and the time of engagement between said arm and said terminal rendered substantially uniform independently of the speed of rotation of the shaft.

4. In a circuitcloser, a rotatable shaft, an arm carried thereby, a terminal including two brushes spaced apart and adapted to engage with the end of said arm as the latter passes therebetween, means for retarding said arm prior to its engagement with the brushes, and a coil spring for moving said arm between said brushes independently of the speed of rotation of the shaft.

5. In a circuit closer, the combination of a substantially stationary casing, a rotatable shaft extending into said casing, an arm carried by said shaft, said arm being formed of two sections, one of which is rigidly secured to said shaft and the other of which is pivoted to the first-mentioned section and movable in respect thereto, a spring for holding said sections in one of their two limiting positions in respect to each other, a terminal carried by said casing and lying in the path of said second-mentioned arm section, and an obstruction carried by said casing adjacent said ter- CLARENCE NOEL ISAACS.

Witnesses CLAIR W. FAIRBANK, EVERARD B. MARsI-IALL. 

